Coagulation AssaysClotting factors are produced by the liver. Hepatic impairment may result in reduced production and abnormality of clotting assays, although functional clotting function may be normal (as pro-coagulant proteins are affected to a similar extent).

INRTest of the extrinsic pathway.

APTTTest of intrinsic pathway.

Metabolic Function

Transaminases are released when liver parenchyma is damaged, and are used to evaluate metabolic function:

ALTNormal range < 54 U.L-1.

ASTNormal range < 35 U.L-1.

Obstructive Tests

ALP (Alkaline Phosphatase)Enzyme involved in dephosphorylation of many compounds. ALP is found in all cells, but particularly in the liver, bile duct, bone, kidney, and placenta.

Normal range is 30-120 U.L-1

GGTEnzyme found in biliary duct.

Normal range:

Males: 11-50 U.L-1

Females: 7-30 U.L-1

BilirubinByproduct of haemaglobin metabolism. May be measured as total, or as conjugated and unconjugated bilirubin.